This invention relates generally to hunting decoys, and pertains more specifically to methods of making hunting decoys by vacuum-forming an outer skin around a buoyant core.
Hunters often use decoys of a particular prey to entice or lure the actual prey toward the hunters. Hunters have come to appreciate that the more realistic the appearance of a decoy, for example, a duck or other water fowl decoy, the more likely that a living like animal will be attracted to the decoy. As such, it is important that hunting decoys be manufactured to simulate the likeness of a desired animal.
To be most effective in use, a decoy should give the appearance of real-life animals, have strength and durability to withstand extreme elements, such as sunlight and cold temperatures, of repeated outdoor use, transport, and storage, be conveniently transported, and be stored in a limited amount of space, while being relatively simple and inexpensive to produce. For water fowl decoys, the decoys must readily float and be supported in a movable and substantially upright, balanced position, so that they may be freely acted upon by movements of the water or by the wind, and thereby more closely imitate realistic flotation characteristics and movements of a particular species.
In the case of hunting duck, or other water fowl, a string of decoys may be floated in a body of water. One potential problem with such decoys is that they, may lie in the line of fire and be inadvertently struck by gun shot. In addition to suffering cosmetic damage, many prior art decoys are rendered useless after being struck by only a few stray gun shot. For example, when hollow, sealed shell decoys are hit by gun shot, they may no longer remain buoyant. When foam decoys are hit by gun shot, they may be obliterated. Thus, a need exists for a decoy which is sufficiently durable to sustain hits by stray gun shot and is still relatively simple and cost effective to manufacture.
Various types of decoys have been manufactured, including full body decoys and half shell, silhouette, cardboard or plastic A-frame, wind sock, and rag decoys, among others. The method of making an improved decoy of the present invention pertains to foam body decoys.
Full body decoys in the prior art are typically manufactured through a xe2x80x9cblow-moldingxe2x80x9d process, in which a whole body decoy is blow-molded, a hole is then drilled in the body, and a filler, such as foam, is finally injected into the body. For example, U.S. Pat. No. 4,450,642 to DeKezel et al. discloses a method of making a decoy including the steps of forming a rigid outer shell, and then injection molding a buoyant plastic material into the shell. A disadvantage of the blow-molding or injection-molding process is that access to or through the interior of the resulting decoy shell is not readily available for filling with buoyant material or for installment of a keel weight, ballast mechanism, or means for connecting a series of decoys together. A hole must be drilled in the decoy shell in order to inject filler material. Generally, another access must be separately created in order to install a keel weight, ballast mechanism, or means for connecting decoys together underwater.
The method of the present invention utilizes a heat-bonding process wherein a sheet of deformable material is heated to the point of elastically deforming and then vacuum-formed about a pre-formed buoyant core body. The sheet of material may be formed about the top portion of the core body, leaving the bottom uncovered, which is advantageous for installing a keel weight or a means for stringing decoys together through the bottom opening.
The sheet of material used in forming the outer skin needs to be sufficiently deformable to become elastic when heated in the manufacturing process in order to collapse and re-form about the buoyant core bodies. Yet the sheet of deformable material needs to also become rigid enough when cooled to provide strength and durability in outdoor use, transportation, and storage.
The rigid outer skin formed by the method of the present invention provides the advantage of being resistant to damage from outdoor elements, and is durable in repeated use, transportation, and storage. The rigid outer skin made by the method of the present invention, in combination with the buoyant core body, gives the appearance of full-bodied animals, produces a decoy that is fully floatable, and requires no further waterproofing, such as with canvas or rubber material or tar. An additional advantage of the rigid outer skin formed about a buoyant core body by the method of the present invention is that the resulting decoy is able to maintain an outer skin integrity and buoyancy even when hit by gun shot.
An advantage of the present invention is that the present invention provides an improved method of making a hunting decoy that reduces or eliminates the disadvantages of current methods of manufacture and to provide hunting decoys with advantageous characteristics.
Another advantage of the present invention is that the present invention provides an improved method of making a hunting decoy that has a buoyant core body.
A further advantage of the present invention provides an improved method of making a hunting decoy that has enhanced tensile strength, flotation and storage stability, and durability of use due to a rigid outer skin.
A still further advantage of the present invention is to provide an improved method of making a hunting decoy utilizing the process of vacuum-forming a sheet of deformable material about a buoyant core body.
Other advantages of the present invention will be apparent to those of ordinary skill in the art of the present invention.
The present invention provides a method for producing a hunting decoy. In a first aspect a method of the present invention comprises: (1) forming a buoyant core body in a shape approximating that of a desired animal from a buoyant core material; and (2) securing a rigid outer skin about the buoyant core body.
The buoyant core body may be formed from a buoyant core material, such as cork, papier-mxc3xa2chxc3xa9, wood, polystyrene, plastic, or canvas. In a preferred embodiment, the process of forming a buoyant core body includes, for example: (a) filling a decoy mold, or body form, with dense particles of polystyrene; (b) expanding the dense polystyrene particles using a combination of heat and steam to form polystyrene beads; (c) xe2x80x9cairing outxe2x80x9d the polystyrene beads to substantially displace the methane gas content resulting from the expansion process from the polystyrene beads; and (d) cooling the resulting buoyant core polystyrene body. As will be understood by those of ordinary skill in the art, the heating of polystyrene may produce methane gas. In a process of the present invention the xe2x80x9cairingxe2x80x9d step is designed to reduce the presence of the methane gas remaining in pores of the polystyrene body. The airing step may be accomplished by allowing the formed body to sit in atmospheric conditions for a period of time sufficient to displace substantially all the methane with ambient air. For an adult duck body, this time period will range from about 12 hours to about 24 hours.
A process of securing a rigid outer skin about the buoyant core body may comprise the following steps: A sheet of deformable material is first heated to its elastic, or collapsing, point. After the sheet of deformable material is heated to its elastic point, the sheet of material is caused to collapse over a buoyant core body, for example, on a vacuum mold. When the buoyant core body is porous, such as when polystyrene is used, suction is then applied through the porous core body. The sheet of heated and collapsed material is preferably vacuum-formed about the buoyant core body by vacuuming out substantially all of the air from underneath the deformed sheet of material. The process of vacuum-forming causes the sheet to adhere tightly about the core body and thus take the shape of the core body. Heating of the pre-formed core body in conjunction with the sheet of material causes the sheet of material and the core body to bond together. Cooling the core body and sheet of material allows the material to anneal, or cure, to further bond to the core body, and to form a rigid outer skin about the core body.
The sheet of deformable material used to form the rigid outer skin may be high impact polystyrene, which is well suited for this application because it is durable, relatively inexpensive, and easy to work with. Those skilled in the art will recognize suitable alternatives, including styrene, acrylic, and acrylonitrile butadiene styrene.
In another aspect a method of the present invention may comprise the steps of forming a buoyant core body in a shape approximating that of a headless desired animal and securing a rigid outer skin about the buoyant core body. The method of the present invention further includes forming a mock head separate from the buoyant core body and securing the mock head to the buoyant core body after the rigid outer skin has been secured about the core body. Forming the buoyant core body without a head provides the advantage of eliminating sharp contours associated with a head, thereby allowing vacuum-forming techniques to effectively be used to apply a rigid outer skin about the buoyant core body. Additionally, the mock head may be formed from excess portions of the sheet of deformable material used to manufacture the rigid outer skin, thereby providing the advantage of eliminating manufacturing waste.
As an example, for one particular embodiment, the steps of this method include: (1) filling a decoy mold, or body form, with dense particles of polystyrene; (2) expanding the dense polystyrene particles using a combination of heat and steam to form polystyrene beads; (3) xe2x80x9cairing outxe2x80x9d the polystyrene beads to substantially displace the methane gas content from the polystyrene beads resulting from the expansion process; (4) cooling the resulting buoyant core polystyrene body; (5) applying an adhesion promoter to the body; (6) heating a thin sheet of polystyrene to its elastic point; (7) causing the polystyrene sheet to collapse over the polystyrene foam core body on a vacuum mold; (8) applying suction through the porous core body; (9) vacuum-forming the sheet over the body, covering the top, sides, and the outermost 0.75 inches above the circumference of the bottom portion of the core body; (10) heating the pre-formed foam core body in conjunction with the polystyrene sheet; (11) cooling the foam core body and the polystyrene sheet to form a rigid outer skin about the core body; (12) trimming excess portions of the sheet with a hot knife; (13) drilling a hole through the rigid outer skin to receive a head; (14) installing a keel weight in the body or core; and (15) painting the body to emulate a particular species of animal.
In application, the method of the present invention produces an improved hunting decoy having a relatively durable shell or outer skin disposed over a buoyant core. The buoyant core facilitates flotation of the decoy, and the outer skin reduces damage due to inadvertent hits from gun shot. The hunting decoy produced by the method of the present invention is therefore strong and durable with respect to extreme elements of repeated outdoor use, transportation, and storage as well as being hit by gun shot, while maintaining a realistic appearance and flotation characteristics and being relatively simple and inexpensive to manufacture.